Delamination Models in Drilling of Composite Materials Using Saw Drill and Candle-Stick Drill

Critical Thrust Force ◽

Drill Design ◽

Abstract Drilling is the most frequently employed operation of secondary machining for fiber-reinforced materials owing to the need for structure joining. Delamination is one of the serious concerns during drilling. Practical experience proves the advantage of using such special drills as saw drill and candle stick drill. Comprehensive delamination models for twist drill, saw drill and candle stick drill in drilling of composite materials are constructed in the present study. Of the three, the saw drill offers the highest critical thrust force followed by the candle stick drill, while the traditional twist drill allows for the lowest thrust force. A guide for drill design can be developed based on the proposed models.

Effect of Peripheral Drilling Moment on Critical Thrust Force Using Twist Drill in Drilling Composite Materials

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.66-68.528 ◽

2011 ◽

Vol 66-68 ◽

pp. 528-533

Author(s):

Chung Chen Tsao

Keyword(s):

Composite Materials ◽

Thrust Force ◽

Construction Materials ◽

Cutting Speed ◽

Practical Experience ◽

Twist Drill ◽

Linear Elastic ◽

Superior Mechanical Properties ◽

Elastic Fracture ◽

Critical Thrust Force

Composites have become valuable construction materials in the aerospace, defense, automobile, and civil industries due to their superior mechanical properties. However, there are significant differences between the machining of metals and alloys and that of composites, because composites are anisotropic and inhomogeneous. Drilling with a conventional twist drill is characterized by a relatively large thrust force due to a negative rake and negligibly small cutting speed at the chisel edge. Such a large thrust force causes defects and damages the composites, leading to poor hole quality, and reduced in-service life under fatigue loads. Although significant efforts have been made to realize the thrust force of twist drill, there are few papers reporting the effect of peripheral drilling moment (torque) on delamination in drilling composite materials. In this paper, an attempt is made to develop the critical thrust of the twist drill with peripheral drilling moment using linear elastic fracture mechanics (LEFM) and energy conservation. The theoretical results agree well with the practical experience in industries.

Effect of Drills with Different Drill Bits on Delamination in Drilling Composite Materials

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.589-590.173 ◽

2013 ◽

Vol 589-590 ◽

pp. 173-178 ◽

Cited By ~ 3

Author(s):

Ying Ying Wei ◽

Jin Yang Xu ◽

Xiao Jiang Cai ◽

Qing Long An ◽

Ming Chen

Keyword(s):

Composite Materials ◽

Thrust Force ◽

Decisive Role ◽

Cutting Parameters ◽

Drill Bit ◽

Twist Drill ◽

Drilling Force ◽

Drill Bits ◽

Critical Thrust Force

Drilling is frequently used in machining of carbon fiber reinforced materials. Twist drill is mostly used in drilling composite materials and some other drills with special drill bits are also needed. Drilling induced delamination is considered one of the most serious problems during machining while drilling force plays a decisive role in delamination. This paper presents the analysis of critical thrust force with special drill bit theoretically. The method of simulation to study the critical thrust force is also introduced. In addition, effect of cutting parameters on delamination by comparing experimental results and mathematical model of twist drill is studied.

Fiber symmetry

10.1093/oso/9780198567783.003.0005 ◽

2017 ◽

Author(s):

David J. Steigmann

Keyword(s):

Composite Materials ◽

Constitutive Equation ◽

Transversely Isotropic ◽

Fiber Reinforced ◽

This chapter develops the general constitutive equation for transversely isotropic, fiber-reinforced materials. Applications include composite materials and bio-elasticity.

Case Study of Consolidation Methods with Fiber-Based Composite Materials in Romania

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.747.414 ◽

2017 ◽

Vol 747 ◽

pp. 414-419

Author(s):

Iasmina Apostol ◽

Rares Bradeanu ◽

Marius Mosoarca

Keyword(s):

Composite Materials ◽

Composite Fiber ◽

Cultural Value ◽

Masonry Buildings ◽

Fiber Reinforced ◽

Made In ◽

Romania is a country divided in two important seismic areas, with a history that has as proof buildings with historical and cultural value, most of them made in masonry. A large number of those buildings have suffered damages because of earthquakes, subsidence of foundations or lack of interventions. In this article will be presented some consolidation methods applied on masonry buildings in Romania, with composite fiber-reinforced materials, made by Kerakoll producer. Those modern consolidation solutions that were used in Romania may represent examples that can represent the base of choosing the consolidation methods for other buildings with similar damages.

Effect of Drilling Force on Delamination of Abaca/Kenaf/Carbon Fiber Reinforced Hybrid Composite

Current Materials Science ◽

10.2174/1874464812666190213111048 ◽

2019 ◽

Vol 12 (1) ◽

pp. 99-105 ◽

Cited By ~ 1

Author(s):

M. Venkatasudhahar ◽

R. Velu

Keyword(s):

Composite Materials ◽

Feed Rate ◽

Hybrid Composite ◽

Natural Fiber ◽

Thrust Force ◽

Fiber Reinforced ◽

Drilling Force ◽

Drill Diameter ◽

Tool Diameter

Background: Natural fiber reinforced materials with polymer matrix finds many applications in industries due to its excellent property. Fiber laminate composite materials have been researched around the globe and were tested to determine its beneficial properties for specific purposes. These composite materials have improved to withstand external loads. However, drilling of composite has remained a difficult task because of its anisotropic material properties. Methods: In this study abaca and kenaf woven mat with the carbon woven mat are laminated using epoxy resin (HY 951) and hardener (LY556) as matrix element while preparing the hybrid composite materials. The drilling operations are carried out using automatic feed computer controlled vertical axis drilling machine. Results: It is found that the drilling force, delamination peel up and push out for the composite material depended on feed rates, drill bit diameters and speeds respectively. The optimal input parameters are obtained using Taguchi L27 orthogonal array, Response Surface Methodology (RSM) and Analysis Of Variance (ANOVA) methods. It is observed that lower feed, smaller drill diameter and moderate speed provided high quality drilled hole. The drilled-hole quality, drilling damages are observed by using profile projector. Conclusion: The following conclusion can be drawn from the present investigation on drilling of reinforced composite materials drilled in different conditions. Feed rate is the important factor compared to the feed and the tool diameter. When feed rate is increased, thrust force also increases. However, thrust force decreases when the cutting speed increases. Feed influenced the thrust force instead of speed and torque during drilling. The drilling induced damages are minimum during lower feed and lower diameter drill. Hence, lower drill diameter, lower feed rate and medium speed are more suitable for drilling the hybrid composites.

The research on precise forming technology of “λ” type composite skin

Composites and Advanced Materials ◽

10.1177/2634983321994749 ◽

2021 ◽

Vol 30 ◽

pp. 263498332199474

Author(s):

Qiang Guo ◽

Kai He ◽

Hengyuan Xu ◽

Youyi Wen

Keyword(s):

Carbon Fiber ◽

Middle Layer ◽

Fiber Reinforced ◽

Process Verification ◽

Forming Technology ◽

New Type ◽

Carbon Fiber Reinforced ◽

Type Composite ◽

With the application of “ λ” type composite skin becoming more and more extensive and diversified, its precise forming technology is also widely concerned. This article mainly solves the quality problems of “ λ” type corner area, such as delamination dispersion and surface wrinkle, which exist in reality commonly in the manufacturing process. The prepreg is heated along the corner area of the tooling to solve the problem that prepreg is difficult to be compacted due to the large modulus of carbon fiber in “ λ” type corner area. Furthermore, two precompaction tests are creatively increased at 16 layers (middle layer) and 32 layers (last layer) for the thick structure, respectively, to ensure the compaction effect of the blank. In addition, combined with the characteristics of highly elastic rubber and carbon fiber-reinforced materials, a new type of soft mold structure with proper flexibility and good stiffness is proposed innovatively through the reasonable placement of carbon fiber-reinforced materials and the setting of exhaust holes according to the structure characteristics of “ λ” type root skin. Through further process verification, it is shown that the improved process has effectively solved the problems of wrinkles and internal delamination at the sharp corners of parts and realized zero-defect manufacturing of “ λ” type root skin for the first time.